1. Technical Field of the Invention
The present invention relates to an image processing apparatus for subjecting input image data to image processing to output to an output device.
2. Description of the Prior Art
In recent years, various systems of output devices have been developed, and image processing apparatuses for performing image processing corresponding to those output devices have also been developed in accordance with each output device. As an example of the output device, a color laser beam printer will be taken up and concretely described here.
The color laser beam printer is capable of printing in various colors using toner amounts of four colors: cyan (hereinafter, C-color), magenta (hereinafter, M-color), yellow (hereinafter, Y-color) and black (hereinafter, k-color). As a representative mechanism for a high-speed color laser beam printer, there are a 4-cycle color printer and a 4-tandem color printer. Also, there is a 2-tandem color printer obtained by fusing the 4-cycle color printer and 4-tandem color printer mechanisms.
FIG. 29 is an explanatory view for illustrating the basic mechanism of the 4-cycle color printer. In FIG. 29, a reference numeral 1 designates a 4-cycle color printer; 2, a tray; 3, sheets; 4, a front roll; 5, a rear roll; 6, a belt; 7, a fixer; 8, a YMCK cleaner; 9, a YMCK drum; 10, a YMCK polygon mirror; 11, a YMCK toner selection box; 12, a Y-toner box; 13; a M-toner box; 14, a C-toner box; and 15, a K-toner box.
In the tray 2, there are stored sheets 3, and a sheet 3 fed from this tray 2 is conveyed through the belt 6. The belt 6 is driven by the front roll 4 and the rear roll 5.
The YMCK toner selection box 11 is provided with the Y-toner box 12 in which Y-color toner is stored, the M-toner box 13 in which M-color toner is stored, the C-toner box 14 in which C-color toner is stored, and the K-toner box 15 in which go K-color toner is stored, and selectively controls any of them.
The surface of the YMCK drum 9 is constructed of photoreceptor, and irradiates light from a light source such as a laser (not shown) onto a writing position on the YMCK drum 9 by the YMCK polygon mirror 10. A portion to which the light has been irradiated becomes charged to form a latent image. The latent image is developed by toner of a color selected by the YMCK toner selection box 11. Thus, the toner is transferred onto the sheet 3. The fixer 7 applies heat to the toner transferred onto the sheet 3 to fix it to the sheet 3. Also, the toner, which has not been transferred onto the sheet 3, but remained on the surface of the YMCK drum 9, and the charge are removed by the YMCK cleaner 8.
Next, a description will be made of the operation of the 4-cycle color printer. FIG. 30 is an explanatory view illustrating the sheet conveying direction, main scanning direction and sub-scanning direction; FIG. 31 is an explanatory view illustrating an example of a method of transmitting image data onto the 4-cycle colorprinter; and FIG. 32 is an explanatory view illuminating an example of timing of transmission and transference of image data onto the 4-cycle color printer. As shown in FIG. 31, plane sequential data of Y-color, M-color, C-color and K-color bit maps are sequentially transmitted to the 4-cycle color printer 1. Generally, one pixel is designated by 8 bits (32 bits of YMCK) each color, and 256 levels of gray can be expressed for each color. Since color is expressed by combinations of Y-color, M-color and C-color, approximately 16,780,000 colors (cube of 256) can be expressed. In this respect, K-color is used to complement the density of Y-color, M-color and C-color. Information of 1 pixel expressed by 8 bits is converted into the irradiation width of laser light. When the maximum width of one pixel is assumed to be., for example, Nmm, in a pixel, to which w (w=0 to 255) has been designated, the laser turns ON between (w/255) and Nmm.
As shown in FIG. 31, of the first page data, an image Y1 is first transmitted to the 4-cycle color printer 1 in the plane sequence. The data of 8-bit each pixel transmitted is converted into irradiation width of laser light. The YMCK polygon mirror 10 irradiates laser light onto the surface of the YMCK drum 9 so that an irradiation position of the laser light moves in the main scanning direction shown in FIG. 30, that is, in a direction perpendicular to the conveying direction of the sheet 3. When the laser turns ON, a portion of the YMCK drum 9, onto which the laser light is irradiated, becomes charged. This charge forms a line of latent image in the main scanning direction.
When a fixed length is outputted in the main scanning direction, the irradiation position of the laser light returns to the starting point of the next line to output one line. The YMCK drum 9 is rotating, and output for each line is repeatedly performed, whereby each line is formed in the sub-scanning direction shown in FIG. 30 to form a two-dimensional latent image on the surface of the YMCK drum 9. Thus, the YMCK toner selection box 11 sets the Y-toner box 12 in advance, whereby Y-color toner adheres to a charged portion of the YMCK drum 9.
Similarly, data of an image M1, an image C1 and an image K1, each of which is data constituting the first page, are fed to the 4-cycle color printer 1 in the plane sequence. At this time, the YMCK toner selection box 11 sets the M-toner box 13, the C-toner box 14 and the K-toner box 15 respectively to cause the M-color toner, the C-color toner and the K-color toner to adhere to the YMCK drum 9.
After data of the image K1 is fed and the K-color toner starts adhering to the YMCK drum 9, the sheet 3 is fed from the tray 2 and is conveyed through the belt 6. Four-color toner adhered to the YMCK drum 9 is transferred onto the sheet 3.
FIG. 32 shows relationship between output timing of images Y1, M1, C1 and K1 on the first page, each of which is image data, and timing transfer 1 in which the image on the first page is transferred onto the sheet 3. This figure shows that timing, at which the image K1, which is the final image data of the first page, is being fed to the 4-cycle color printer 1 overlaps with transfer 1, which is timing at which transfer is being made onto the sheet 3. During this lapping, the data of the image K1 is converted into irradiation width of laser light, the laser light is irradiated onto the YMCK drum 9 from the YMCK polygon mirror 10, and the K-color toner adheres to the YMCK drum 9. Thus, toner of four colors is transferred onto the sheet 3.
Also, after the completion of the transfer of toner onto the sheet 3, it is necessary to clear any remaining toner, which remained on the YMCK drum 9 and could not be transferred onto the sheet, and the charged portion. This treatment is performed by the YMCK cleaner 8. At timing at which feeding out of the image K1 and the transfer 1 overlap, the clearing treatment using the YMCK cleaner 8 is also being partially performed at the same time. At timing at which the image K1 is not transmitted, but only the transfer 1 takes place, only the transfer onto the sheet 3 and clearing treatment using the YMCK cleaner 8 are performed.
After the image data of the first page is transmitted, image Y2 data, which is data constituting the second page, is fed to the 4-cycle color printer 1 in the plane sequence. In this respect, in FIG. 32, at timing at which the transfer 1 and the image Y2 are overlapping, the image Y2 data is converted into irradiation width of laser light while the clearing treatment using the YMCK cleaner 8 is being partially performed, and laser is irradiated onto the YMCK drum 9 from the YMCK polygon mirror 10 for charging, and Y-color toner adheres.
After one-page image data is all transmitted onto the 4-cycle color printer 1 to transfer four colors of toner onto the sheet 3, the fixer 7 applies heat to the sheet 3 and toner transferred onto the sheet 3 to fix the toner. When fixing of the toner onto the sheet 3 is completed, a recording operation on the first page is terminated. Similarly, the second page is also processed. By repeatedly performing such a process, images are formed on plural pages.
FIG. 33 is an explanatory view illustrating a basic mechanism for a 4-tandem color printer. In FIG. 33, components equivalent to those in FIG. 29 are represented by the same reference numbers. A reference numeral 21 designates the 4-tandem color printer; 22, a Y-cleaner; 23, a Y-drum; 24, a Y-polygon mirror; 25, a Y-toner box; 26, an M-cleaner; 27, an M-drum; 28, an M-polygon mirror; 29, an M-toner box; 30, a C-cleaner; 31, a C-drum; 32, a C-polygon mirror; 33, a C-toner box; 34, a K-cleaner; 35, a K-drum; 36, a K-polygon mirror; and 37, a K-toner box.
The 4-tandem color printer 21 is configured by providing a group of the drum, the polygon mirror, the toner box and the cleaner for toner of each color on a conveying path of a sheet. Four groups for each of the Y-color, the M-color, the C-color and the K-color are provided here.
The surface of the Y drum 23 is constructed of a photoreceptor, and irradiates light from a light source such as a laser (not shown) onto a writing position on the Y drum 23 through the Y polygon mirror 24. A portion to which the light has been irradiated becomes charged to form a latent image. The latent image is developed by toner of Y-color in the Y-toner box 25. Thus, the Y-toner is transferred onto the sheet 3. The toner, which has not been transferred onto the sheet 3, but remained on the surface of the Y-drum 23, and the charge are removed by the Y-cleaner 22.
Similarly, the surface of the M-drum 27 is constructed of photoreceptor, and irradiates light from a light source such as a laser (not shown) onto a writing position on the M drum 27 through the M polygon mirror 28. A portion to which the light has been irradiated becomes charged to form a latent image. The latent image is developed by toner of M-color in the M-toner box 29. Thus, the M-toner is transferred onto the sheet 3. The toner, which has not been transferred onto the sheet 3 but remained on the surface of the M-drum 27, and the charge are removed by the M-cleaner 26.
The surface of the C-drum 31 is also similarly constructed of a photoreceptor, and irradiates light from a light source such as a laser (not shown) onto a writing position on the C-drum 31 through the C polygon mirror 32. A portion to which the light has been irradiated becomes charged to form a latent image. The latent image is developed by toner of C-color in the C-toner box 33. Thus, the C-toner is transferred onto the sheet 3. The toner, which has not been transferred onto the sheet 3 but remained on the surface of the C-drum 31, and the charge are removed by the C-cleaner 30.
The surface of the K-drum 35 is also similarly constructed of a photoreceptor, and irradiates light from a light source such as a laser (not shown) onto a writing position on the K-drum 35 through the K polygon mirror 36. A portion to which the light has been irradiated becomes charged to form a latent image. The latent image is developed by toner of K-color in the K-toner box 37. Thus, the K-toner is transferred onto the sheet 3. The toner, which has not been transferred onto the sheet 3 but remained on the surface of the K-drum 37, and the charge are removed by the K-cleaner 34.
In the tray 2, there are stored sheets 3, and a sheet 3 fed from this tray 2 is conveyed through the belt 6. The belt 6 is driven by the front roll 4 and the rear roll 5. In the course of process, in which the sheet 3 is conveyed through the belt 6, Y-toner is transferred from the Y-drum 23, M-toner is transferred from the M-drum 27, C-toner is transferred from the C-drum 31, and K-toner is transferred from the K-drum 35. Thus, the fixer 7 applies heat to toner of four colors transferred onto the sheet 3 to fix onto the sheet.
Next, a description will be made of the operation of the 4-tandem color printer 21. FIG. 34 is an explanatory view illustrating an example of a method of transmitting image data onto the 4-tandem color printer; and FIG. 35 is an explanatory view illustrating an example of timing of transmission and transference of image data onto the 4-tandem color printer. To the 4-tandem color printer 21, plane sequence data of Y-color, M-color, C-color and K-color bit maps are transmitted in parallel with somewhat timing drift as shown in FIG. 34.
The image Y1, which is data of the first page, is transmitted to the 4-tandem color printer 21 in the plane sequence. The data of the image Y1 of 8-bit each pixel transmitted is converted to width when the laser turns ON. The Y-polygon mirror 24 outputs one line of image data in the main scanning direction of the sheet 3. When the Y-drum 23 is rotating and a fixed length is outputted in the main scanning direction, the irradiating position of the laser light returns to the starting point of the next line to output one-line. A portion of the Y-drum 23 which has received light when the laser turns ON becomes charged to form a latent image. The Y-toner box 25 causes Y-color toner to adhere to the latent image portion charged.
Data of an image M1, an image C1 and an image K1, which is data constituting one page similarly, are transmitted to the 4-tandem color printer 21 in the plane sequence, and M-color toner, C-color toner and K-color toner adhere to the M-drum 27, the C-drum 31 and the K-drum 35 respectively depending on the image data as the image Yl has been processed. The toner adhered to each drum is transferred onto the sheet 3.
FIG. 35 shows timing in this process. When printing of the first page is started, data of the image Y1 is first transmitted to the 4-tandem color printer 21, is converted into irradiation width of laser light to charge the Y-drum 23 with electricity, and the Y-toner box 25 causes Y-color toner to adhere to the Y-drum 23. On the other hand, the sheet 3 is fed from the tray 2, is conveyed through the belt 6 and Y-color toner adhered to the Y-drum 23 is transferred onto the sheet 3. The Y-color toner, which has not been transferred onto the sheet 3 but remained on the Y-drum 23, and the charged portion are cleared by the Y-cleaner 22. At this time, the charging with electricity by laser, adhesion of the Y-color toner, transference onto the sheet 3 and the clearing treatment by the Y-cleaner 22 take place on the Y-drum 23 at the same time. The same things take place on the image M1, the image C1, and the image K1 with temporal drift as shown in FIG. 35. After the completion of transference of Y-color toner, M-color toner, C-color toner and K-color toner onto the sheet 3, the fixer 7 applies heat to the toner to fix to the sheet 3. Thus, when the sheet 3 is discharged from the printer, the recording operation for the first page is completed. The operations for the second page and after will be performed in the same way to complete a series of recording operations.
FIG. 36 is an explanatory view illustrating a basic mechanism for a 2-tandem color printer. In FIG. 36, components equivalent to those in FIG. 29 are represented by the same reference numbers. A reference numeral 41 designates the 2-tandem color printer; 42, a YM-cleaner; 43, a YM-drum; 44, a YM-polygon mirror; 45, a YM-toner selection box; 46, a Y-toner box; 47, an M-toner box; 48, a CK-cleaner; 49, a CK-drum; 50, a CK-polygon mirror; 51, a CK-toner selection box; 52, a C-toner box; and 53, a K-toner box.
The 2-tandem color printer 41 is configured by providing two groups; each group including the drum, the polygon mirror, the toner selection box including a two-color toner box and the cleaner, for toner of each color on a conveying path of a sheet. The configuration is arranged here so that either Y-color and M-color, or C-color and K-color are selectively used.
The surface of the YM drum 43 is constructed of a photoreceptor, and irradiates light from a light source such as a laser (not shown) onto a writing position on the YM drum 43 through the YM-polygon mirror 44. A portion to which the light has been irradiated becomes charged to form a latent image. The YM toner selection box 45 is provided with the Y-toner box 46 and the M-toner box 47, either of which is selected. A latent image formed on the YM-drum 43 is developed by the use of toner of a color selected by the YM-toner selection box 45.
The surface of the CK drum 49 is similarly constructed of a photoreceptor, and irradiates light from a light source such as a laser (not shown) onto a writing position on the CK drum 49 through the CK polygon mirror 50. A portion to which the light has been irradiated becomes charged to form a latent image. The CK toner selection box 51 is provided with the C-toner box 52 and the K-toner box 53, either of which is selected. A latent image formed on the CK-drum 49 is developed by the use of toner of a color selected by the CK-toner selection box 51.
In the tray 2, there are stored sheets 3, and a sheet 3 fed from this tray 2 is conveyed through the belt 6. The belt 6 is driven by the front roll 4 and the rear roll 5. In the course of process, in which the sheet 3 is conveyed through the belt 6, Y-toner and M-toner are transferred from the YM-drum 43, and C-toner and K-toner are transferred from the CK-drum 49. Thus, the fixer 7 applies heat to toner of four colors transferred onto the sheet 3 to fix onto the sheet. In this respect, the toner, which has not been transferred onto the sheet 3 but remained on the surface of the YM-drum 43, and the charge are removed by the YM-cleaner 42. Also, the toner, which has not been transferred onto the sheet 3 but remained on the surface of the CK-drum 49, and the charge are removed by the CK-cleaner 48.
Next, a description will be made of the operation of the 2-tandem color printer 41. FIG. 37 is an explanatory view illustrating an example of a method of transmitting image data to the 2-tandem color printer; and FIG. 38 is an explanatory view illustrating an example of timing of transmission and transference of image data onto the 2-tandem color printer. To the 2-tandem color printer 41, Y-color and M-color are in sequence transmitted, and C-color and K-color are in sequence transmitted as plane sequence data of bit maps as shown in FIG. 37.
The image Y1, which is data of the first page, is transmitted to the 2-tandem color printer 41 in the plane sequence. The data of the image Y1 of 8-bit each pixel transmitted is converted to the irradiation width of laser light. The YM-polygon mirror 44 outputs one line of image data in the main scanning direction. When the YM-drum 43 is rotating and a fixed length is outputted in the main scanning direction, the irradiating position of the laser light returns to the starting point of the next line to output one line. A portion of the YM-drum 43, which has been irradiated with laser light, is charged with electricity. The YM-toner selection box 45 has set the Y-toner box 46 and Y-color toner adheres to the portion charged.
When the processing of the image Y1 is completed, the YM toner selection box 45 sets the M-toner box 47, and the image M1 is transmitted to the 2-tandem color printer 41. The image M1 causes the YM-polygon mirror 44 to irradiate the YM-drum 43 with laser light for charging, and causes M-color toner to adhere. After the transmission of the image M1 is started, the sheet 3 is fed from the tray 2, is conveyed through the belt 6, and Y-color toner and M-color toner are transferred onto the sheet 3. The Y-color toner and M-color toner, which have not been transferred onto the sheet 3 but remained on the YM-drum 43, and the charged portion are cleared by the YM-cleaner 42.
In this course, on the YM-drum 43, there are performed the charging by laser light, adhesion of the M-color toner, transference of Y-color toner and M-color toner onto the sheet 3 and the clearing treatment by the YM-cleaner 42 at the same time.
As shown in FIG. 38, images C1 and K1 are also subjected to the same processing, with temporal drift, as the processing on the images Y1 and M1 described above. After Y-color toner and M-color toner are transferred onto the sheet 3 to be conveyed, the sheet 3 is further conveyed and C-color toner and K-color toner are transferred onto it. After the completion of transference of Y-color toner, M-color toner, C-color toner and K-color toner onto the sheet 3, the fixer 7 applies heat to the toner to fix to the sheet 3. Thus, when the sheet 3 is discharged from the printer, the printing operation for the first page is completed. The similar operation will be performed on the second page and after to complete a series of recording operations.
Next, a description will be made of an image processing apparatus for outputting data to such a 4-cycle color printer 1, a 4-tandem color printer 21 and a 2-tandem color printer 41 as described above. In the image processing apparatus, a PDL (language obtained by describing data to be outputted from a printer), which is transmitted from a personal computer, a work station or the like for printing, is converted into an intermediate language which can be processed by internal hardware. Thus, at a speed capable of following a data output speed to a printer at the time of outputting to a color printer, the intermediate language is converted into bit map data for outputting to the color printer.
The capacity of memory required for rendering and storing bit map data on outputting to the color printer is approximately 140 MB (mega byte) at resolution of 600 DPI and at 8-bit each color of YMCK using A4 in sheet size. Also, in order to continuously feed bit map data to the color printer, memory for storing data in the print and memory for rendering data of the next page are required, and therefore, memory of approximately 280 MB will be required.
Although memory of such large capacity may, of course, be mounted, it becomes very expensive as a system. Therefore, in order to implement a low-priced system, a system using an intermediate language and a band buffer has been worked out. FIG. 39 is an explanatory view illustrating an example of a recording operation using the intermediate language and the band buffer. In FIG. 39, a reference numeral 61 designates PDL; 62 to 65, intermediate languages; 66 and 67, band buffers; and 68, a formed image. FIG. 39 shows an operation in a system having two band buffers, each band buffer having a size obtained by dividing data of one page into four. A PDL 61 is transmitted from a personal computer, a work station or the like. Here, it is assumed as an example that instructions for rendering a Circle, a Character xe2x80x9cAxe2x80x9d and a Rectangle have been described in the PDL 61.
The information of the PDL 61 is converted into intermediate languages in units of bands divided into four. As the first band, an intermediate language 62 of band 1, which is an intermediate language for rendering a circle, is generated. As the next band 2, an intermediate language 63 of band 2, which is an intermediate language for rendering a character xe2x80x9cAxe2x80x9d, is generated. As the next band 3, an intermediate language 64 of band 3 for rendering R1, which is a portion of a rectangle, is generated. As the last band 4, an intermediate language 65 of band 4 for rendering R2, which is a portion of a rectangle, is generated.
The band buffer is constructed of two band buffers 66 and 67, each of which has a size obtained by dividing one page into four. When printing is performed by a color printer, the intermediate language 62 of band 1 is rendered on the band buffer 66 as bit map data, and output to the printer is started after completion of the rendering. The intermediate language 63 of band 2 is rendered on the band buffer 67 as bit map data while data of the band buffer 66 is being outputted to the printer, and after the completion of the rendering, there is a wait till the output of the band buffer 66 to the color printer is completed.
After the completion of the output of the band buffer 66, the bit map data is subsequently outputted from the band buffer 67. At the same time, the band buffer 66 is cleared (background color is written on the entire surface), the intermediate language 64 of band 3 is rendered on the band buffer 66 as bit map data, and after the completion of the rendering, there is a wait till the output of the band buffer 67 to the color printer is completed.
After the completion of the output of the band buffer 67, the bit map data is subsequently outputted from the band buffer 66. At the same time, the band buffer 67 is cleared (background color is written on the entire surface), the intermediate language 65 of band 4 is rendered on the band buffer 67 as bit map data, and after the completion of the rendering, there is a wait till the output of the band buffer 66 to the color printer is completed.
After the completion of the output of the band buffer 66, the bit map data is subsequently outputted from the band buffer 67. After the completion of the data output from the band buffer 67, data output of one page is completed to complete the printing.
The memory for use in this way is band buffers 66 and 67, each of which has capacity of one quarter of one page. In other words, memory for printing requires a half of the memory required for rendering one page. In a case where one page is divided into 32, it is possible to implement a system capable of printing with memory of one sixteenth.
FIG. 40 is a block diagram showing an example of an image processing apparatus corresponding to the 4-cycle color printer. In FIG. 40, a reference numeral 71 designates an image processing apparatus corresponding to the 4-cycle color printer; 72, a CPU; 73, a bus bridge; 74, system memory; 75, a PDL; 76, an intermediate language; 77, a YMCK rendering processor; 78, a YMCK band buffer; 79, a YMCK output control unit; and 80, a bus. In this respect, the configuration of the 4-cycle color printer 1 is as shown in FIG. 29, and components equivalent to those in FIG. 29 are represented by the same reference numbers.
The image processing apparatus 71 corresponding to the 4-cycle color printer has a CPU 72, a system memory 74, a YMCK rendering processor 77, a YMCK output control unit 79 and the like, and the CPU 72, the system memory 74 and the bus 80 are connected together through the bus bridge 73. The CPU 72 controls the image processing apparatus 71 corresponding to the 4-cycle color printer, and performs a process of converting the PDL 75 into the intermediate language 76. The system memory 74 stores the PDL 75 and the intermediate language 76. The YMCK rendering processor 77 converts the intermediate language 76 into bit map data. The YMCK rendering processor 77 has the YMCK band buffer 78, in which bit map data for at least two bands can be written. The YMCK output control unit 79 outputs bit map data rendered on the YMCK band buffer 78 to the 4-cycle color printer 1.
A description will be made of a basic operation of the image processing apparatus 71 corresponding to the 4-cycle color printer. When an instruction to print is issued to the 4-cycle color printer 1 from a personal computer, a work station or the like, the PDL 75 is generated and is transmitted to the image processing apparatus 71 corresponding to the 4-cycle color printer. At this time, the CPU 72 performs communication processing with the.personal computer, the work station or the like. The PDL 75 transmitted is stored in the system memory 74. The CPU 72 performs a process of converting the PDL 75 into an intermediate language 76 which can be processed by the YMCK rendering processor 77. After the completion of the conversion process into the intermediate language 76, the CPU 72 issues an instruction to start printing to the YMCK rendering processor 77.
The YMCK band buffer 78 within the YMCK rendering processor 77 is divided into two, and when one is outputting bit map data to the 4-cycle color printer 1, the other is used for processing to render the bit map data from the intermediate language 76. On the receipt of an instruction to start printing, the YMCK rendering processor 77 automatically reads the intermediate language 76 existing on the system memory 74 to generate Y-color bit map data to the YMCK band buffer 78. When the Y-color bit map data is generated, the YMCK output control unit 79 starts data output to the 4-cycle color printer 1. The YMCK rendering processor 79 renders the next band while outputting the data to the 4-cycle color printer 1, to generate bit map data. By the use of the YMCK band buffer 78 divided into two, all the bands are rendered to complete the output of the Y-color bit map data.
Similarly, M-color bit map data, C-color bit map data and K-color bit map data are sequentially outputted to the 4-cycle color printer 1 to complete the printing of one page.
FIG. 41 is a block diagram showing an example of an image processing apparatus corresponding to the 4-tandem color printer. In FIG. 41, components equivalent to those in FIG. 40 are represented by the same reference numbers, and a description thereof will be omitted. A reference numeral 81 designates an image processing apparatus corresponding to the 4-tandem color printer; 82, a Y-rendering processor; 83, a Y-band buffer; 84, a Y-output control unit; 85, an M-rendering processor; 86, an M-band buffer; 87, an M-output control unit; 88, a C-rendering processor; 89, a C-band buffer; 90, a C-output control unit; 91, a K-rendering processor; 92, a K-band buffer; and 93, a K-output control unit. In this respect, the configuration of the 4-tandem color printer 1 is as shown in FIG. 33, and components equivalent to those in FIG. 33 are represented by the same reference numbers.
The image processing apparatus 81 corresponding to the 4-tandem color printer has a CPU 72, a system memory.74, the Y-rendering processor 82, the Y-output control unit 84, the M-rendering processor 85, the M-output control unit 87, the C-rendering processor 88, the C-output control unit 90, the K-rendering processor 91, the Y-output control unit 93 and the like. Also, the CPU 72, the system memory 74 and the bus 80 are connected together through the bus bridge 73.
The Y-rendering processor 82 converts the intermediate language 76 into Y-color bit map data. The Y-rendering processor 82 has the Y-band buffer 83, in which Y-color bit map data for at least two bands can be written. The Y-output control unit 84 outputs bit map data rendered on the Y-band buffer 83 to the 4-tandem color printer 21.
The M-rendering processor 85 converts the intermediate language 76 into M-color bit map data. The M-rendering processor 85 has the M-band buffer 86, in which M-color bit map data for at least two bands can be written. The M-output control unit 87 outputs bit map data rendered on the M-band buffer 86 to the 4-tandem color printer 21.
The C-rendering processor 88 converts the intermediate language 76 into C-color bit map data. The C-rendering processor 88 has the C-band buffer 89, in which C-color bit map data for at least two bands can be written. The C-output control unit 90 outputs bit map data rendered on the C-band buffer 89 to the 4-tandem color printer 21.
The K-rendering processor 91 converts the intermediate language 76 into K-color bit map data. The K-rendering processor 91 has the K-band buffer 92, in which K-color bit map data for at least two bands can be written. The K-output control unit 93 outputs bit map data rendered on the K-band buffer 92 to the 4-tandem color printer 21.
A description will be made of a basic operation of the image processing apparatus 81 corresponding to the 4-tandem color printer. When an instruction to print is issued to the 4-tandem color printer 21 from a personal computer, a work station or the like, the PDL 75 is generated and is transmitted to the image processing apparatus 81 corresponding to the 4-tandem color printer. At this time, the CPU 72 performs communication processing with the personal computer, the work station or the like. The PDL 75 transmitted is stored in the system memory 74. The CPU 72 performs a process of converting the PDL 75 into an intermediate language 76 which can be processed by the Y-rendering processor 82, the M-rendering processor 85, the C-rendering processor 88, and the K-rendering processor 91. After the completion of the conversion process into the intermediate language 76, the CPU 72 issues an instruction to start printing to the Y-rendering processor 82, the M-rendering processor 85, the C-rendering processor 88, and the K-rendering processor 91.
The Y-band buffer 83 is divided into two, and when one is outputting bit map data to the 4-tandem color printer 21, the other is used for processing to render the bit map data from the intermediate language 76. On the receipt of an instruction to start printing, the Y-rendering processor 82 automatically reads the intermediate language 76 existing on the system memory 74 to generate Y-color bit map data to the Y band buffer 83.
When the Y-color bit map data is generated, the Y-output control unit 84 starts data output to the 4-tandem color printer 21. The Y-rendering processor 82 renders the next band while outputting bit map data to the 4-tandem color printer 21 through the Y-output control unit 84, to generate bit map data. By the use of the Y-band buffer 83 divided into two, all the bands are rendered and the data thus rendered is outputted to complete the output of the Y-color bit map data.
When the Y-output control unit 84 starts to transmit bit map data to the 4-tandem color printer 21, the M-rendering processor 85 automatically reads the intermediate language 76 to start generation of M-color bit map data in the M-band buffer 86. On receipt of a request from the 4-tandem color printer 21 to transmit the M-color bit map data, the M-output control unit 87 starts output of the M-color bit map data. While outputting bit map data to the 4-tandem color printer 21 through M-output control unit 87, the M-rendering processor 85 renders the next band to generate bit map data. By the use of the M-band buffer 86 divided into two, all the bands are rendered and the data thus rendered is outputted to complete the output of the M-color bit map data.
When the M-output control unit 87 starts to transmit bit map data to the 4-tandem color printer 21, the C-rendering processor 88 automatically reads the intermediate language 76 to start generation of C-color bit map data in the C-band buffer 89. On receipt of a request from the 4-tandem color printer 21 to transmit the C-color bit map data, the C-output control unit 90 starts output of the C-color bit map data. While outputting the data to the 4-tandem color printer 21 through C-output control unit 90, the C-rendering processor 88 renders the next band to generate bit map data. By the use of the C-band buffer 89 divided into two, all the bands are rendered and the bit map data thus rendered is outputted to complete the output of the C-color bit map data.
When the C-output control unit 90 starts to transmit bit map data to the 4-tandem color printer 21, the K-rendering processor 91 automatically reads the intermediate language 76 to start generation of K-color bit map data in the K-band buffer 92. On receipt of a request from the 4-tandem color printer 21 to transmit the K-color bit map data, the K-output control unit 93 starts output of the K-color bit map data. While outputting the bit map data to the 4-tandem colorprinter 21 through K-output control unit 93, the K-rendering processor 91 renders the next band to generate bit map data. By the use of the K-band buffer 92 divided into two, all the bands are rendered and the bit map data thus rendered is outputted to complete the output of the K-color bit map data. The above-described processing completes printing of one page.
FIG. 42 is a block diagram showing an example of an image processing apparatus corresponding to the 2-tandem color printer. In FIG. 42, components equivalent to those in FIG. 40 are represented by the same reference numbers, and a description thereof will be omitted. A reference numeral 101 designates an image processing apparatus corresponding to the 2-tandem color printer; 102, a YM-rendering processor; 103, a YM-band buffer; 104, a YM-output control unit; 105, a CK-rendering processor; 106, a CK-band buffer; and 107, a CK-output control unit. In this respect, the configuration of the 2-tandem color printer 41 is as shown in FIG. 36, and components equivalent to those in FIG. 36 are represented by the same reference numbers.
The image processing apparatus 101 corresponding to the 2-tandem color printer has a CPU 72, a system memory 74, a YM-rendering processor 102, a YM-output control unit 104, a CK-rendering processor 105, a CK-output control unit 107 and the like. Also, the CPU 72, the system memory 74 and the bus 80 are connected together through the bus bridge 73.
The YM-rendering processor 102 converts the intermediate language 76 into bit map data of Y-color and M-color. The YM-rendering processor 102 has the YM-band buffer 103, in which bit map data of Y-color and M-color for at least two bands can be written. The YM-output control unit 104 outputs bit map data rendered on the YM-band buffer 103 to the 2-tandem color printer 41.
The CK-rendering processor 105 converts the intermediate language 76 into bit map data of C-color and K-color. The CK-rendering processor 105 has the CK-band buffer 106, in which bit map data of C-color and K-color for at least two bands can be written. The CK-output control unit 107 outputs bit map data rendered on the CK-band buffer 106 to the 2-tandem color printer 41.
A description will be made of a basic operation of the image processing apparatus 101 corresponding to the 2-tandem color printer. When an instruction to print is issued to the 2-tandem color printer 41 from a personal computer, a work station or the like, the PDL 75 is generated and is transmitted to the image processing apparatus 101 corresponding to the 2-tandem color printer. At this time, the CPU 72 performs communication processing with the personal computer, the work station or the like. The PDL 75 transmitted is stored in the system memory 74. The CPU 72 performs a process of converting the PDL 75 into an intermediate language 76 which can be processed by the YM-rendering processor 102 and the CK-rendering processor 105. After the completion of the conversion process into the intermediate language 76, the CPU 72 issues an instruction to start printing to the YM-rendering processor 102 and the CK-rendering processor 105.
The YM-band buffer 103 is divided into two, and when one is outputting bit map data to the 2-tandem color printer 41, the other is used for processing to render the bit map data from the intermediate language 76. On the receipt of an instruction to start printing, the YM-rendering processor 102 automatically reads the intermediate language 76 existing on the system memory 74 to generate Y-color bit map data to the YM-band buffer 103. When the Y-color bit map data is generated, the YM-output control unit 104 starts output of bit map data to the 2-tandem color printer 41. The YM-rendering processor 102 renders the next band while outputting bit map data to the 2-tandem color printer 41 through the YM-output control unit 104, to generate bit map data. By the use of the YM-band buffer 103 divided into two, all the bands are rendered and the data thus rendered is outputted to complete the output of the Y-color bit map data.
Subsequently, the YM-rendering processor 102 starts generation of M-color bit map data. It automatically reads the intermediate language 76 existing on the system memory 74 to generate M-color bit map data in the YM band buffer 103. When the M-color bit map data is generated, the YM output control unit 104 starts output of bit map data to the 2-tandem color printer 41. While outputting the bit map data to the 2-tandem color printer 41 through YM-output control unit 104, the YM-rendering processor 102 renders the next band to generate bit map data. By the use of the YM-band buffer 103 divided into two, all the bands are rendered and the bit map data thus rendered is outputted to complete the output of the M-color bit map data.
When the YM-output control unit 104 starts to transmit the bit map data to the 2-tandem color printer 41, the CK-rendering processor 105 automatically reads the intermediate language 76 to start generation of C-color bit map data in the CK-band buffer 106. On receipt of a request from the 2-tandem color printer 41 to transmit the C-color bit map data, the CK-output control unit 107 starts output of the C-color bit map data. While outputting the bit map data to the 2-tandem color printer 41 through CK-output control unit 107, the CK-rendering processor 105 renders the next band to generate bit map data. By the use of the CK-band buffer 106 divided into two, all the bands are rendered and the bit map data thus rendered is outputted to complete the output of the C-color bit map data.
Subsequently, the CK-rendering processor 105 generates K-color bit map data. It automatically reads the intermediate language 76 existing on the system memory 74 to generate K-color bit map data in the CK band buffer 106. When the K-color bit map data is generated, the CK output control unit 107 starts output of bit map data to the 2-tandem color printer 41. While outputting the bit map data to the 2-tandem color printer 41 through CK-output control unit 107, the CK-rendering processor 105 renders the next band to generate bit map data. By the use of the CK-band buffer 106 divided into two, all the bands are rendered and the bit map data thus rendered is outputted to complete the output of the K-color bit map data.
As described above, the color printer has different configuration of an image processing apparatus for generating bit map data to be outputted to the color printer depending upon its mechanism. In the above-described description, the description has been made focusing attention to the configuration of the image processing apparatus, but not only the configuration but also the throughput capacity required differs. Hereinafter, a description will be made of the throughput capacity required for the image processing apparatus in each color printer.
FIG. 43 is an explanatory view illustrating a concrete example of record processing using a band buffer having a size of one eighth of one page; and FIG. 44 is likewise an explanatory view illustrating relationship between a band management unit and intermediate languages for each band to be managed. In FIGS. 43 and 44, a reference numeral 111 designates a PDL; 112, images indicated by the PDL 111; 113, 121 to 128, band data; 114, a band management unit; and 115, an intermediate language group. Here, as an example, it is assumed that the PDL 111 describing the image 112 is inputted into the image processing apparatus as shown in FIG. 43 and is converted into intermediate languages divided for each band having a size of one eighth of one page. Although the band data 113 is actually not bit-map-expanded, an image bit-map-expanded is shown for the sake of clarity. The intermediate language group 115 divided for each band in this way is managed by the band management unit 114 respectively as shown in FIG. 44.
Let us consider a case where the PDL 111 as shown in FIG. 43 is printed by a 4-cycle color printer 1, a 4-tandem color printer 21 and a 2-tandem color printer 41 having a printing speed of NPPM (Page Per Minute: a number of pages which can be printed a minute) by the use of a conventional image processing apparatus 71 corresponding to the 4-cycle color printer, an image processing apparatus 81 corresponding to the 4-tandem color printer, and an image processing apparatus 101 corresponding to the 2-tandem color printer. In this respect, image 112 shown in FIG. 43 can be obtained by printing by each color printer.
In the image processing apparatus 71 corresponding to the 4-cycle color printer, the image processing apparatus 81 corresponding to the 4-tandem color printer, and the image processing apparatus 101 corresponding to the 2-tandem color printer, the PDL 111 is converted into the intermediate language group 115, is further converted into bit map data by the use of band buffers divided into eight, and is outputted to the 4-cycle color printer 1, the 4-tandem color printer 21 and the 2-tandem color printer 41.
FIG. 45 is a timing chart when bit map data for each band is transmitted onto the 4-cycle color printer in the conventional image processing apparatus corresponding to the 4-cycle color printer. Here, there are shown the operations of the YMCK rendering processor 77 for rendering (generating) bit map data from the intermediate language and the YMCK output control unit 79 for controlling the output to the 4-cycle color printer 1 in the image processing apparatus 71 corresponding to the 4-cycle color printer.
Also, FIG. 46 is a timing chart when bit map data for each band is transmitted onto the 4-tandem color printer in the conventional image processing apparatus corresponding to the 4-tandem color printer. Here, in the image processing apparatus 81 corresponding to the 4-tandem color printer, there are shown the operations of the Y-rendering processor 82, the M-rendering processor 85, the C-rendering processor 88, and the K-rendering processor 91, which render (generate) bit map data from the intermediate language, and the Y-output control unit 84, the M-output control unit 87, the C-output control unit 90 and the K-output control unit 93, which control the output to the 4-tandem color printer 21.
Further, FIG. 47 is a timing chart when bit map data for each band is transmitted onto the 2-tandem color printer in the conventional image processing apparatus corresponding to the 2-tandem color printer. Here, in the image processing apparatus 101 corresponding to the 2-tandem color printer, there are shown the operations of the YM-rendering processor 102 and the CK-rendering processor 105, which render (generate) bit map data from the intermediate language, and the YM-output control unit 104 and the CK-output control unit 107, which control the output to the 2-tandem color printer 41. In this respect, in FIGS. 45 to 47, (1) to (8) correspond to bands (1) to (8) divided into eight.
Here, attention is focused on the rendering processor in the image processing apparatus. When time given to process one band is assumed to be T seconds in the YMCK rendering processor 77 of the image processing apparatus 71 corresponding to the 4-cycle color printer, the time is approximately 4T seconds in the Y-rendering processor 82, the M-rendering processor 85, the C-rendering processor 88, and the K-rendering processor 91 in the image processing apparatus 81 corresponding to the 4-tandem color printer. Further, the time becomes approximately 2T seconds in the YM-rendering processor 102 and the CK-rendering processor 105 of the image processing apparatus 101 corresponding to the 2-tandem color printer. More specifically, when rendering performance of the Y-rendering processor 82, the M-rendering processor 85, the C-rendering processor 88, and the K-rendering processor 91 in the image processing apparatus 81 corresponding to the 4-tandem color printer is assumed to be 1, the performance twice as good is required for the YM-rendering processor 102 and the CK-rendering processor 105 in the image processing apparatus 101 corresponding to the 2-tandem color printer. Further, the performance four times as good is required for the YMCK rendering processor 77 in the image processing apparatus 71 corresponding to the 4-cycle color printer.
When developing an image processing apparatus for controlling a color printer, the development is preferably performed with less expenses. In this case, it can be conceived that the YMCK rendering processor 77 and the YMCK output control unit 79, for which the highest performance is required, are developed as one 4-cycle ASIC, and in the image processing apparatus 71 corresponding to the 4-cycle color printer, the system is constructed of one piece of this 4-cycle ASIC. Also, it can be conceived that in the image processing apparatus 101 corresponding to the 2-tandem color printer, the system is constructed of two pieces of the 4-cycle ASIC, and that in the image processing apparatus 81 corresponding to the 4-tandem color printer, the system is constructed of four pieces of the 4-cycle ASIC.
In the image processing apparatus 81 corresponding to the 4-tandem color printer, however, it becomes very excessive in specification and the cost is increased because it is possible to output to the color printer with performance of a quarter of the 4-cycle ASIC. Also, since four pieces of 4-cycle ASIC are connected to the bus, the substrate also becomes larger, and the cost is increased. Further, since a number of devices are connected to the bus, there arises a limit to increasing the clock speed. Even in the image processing apparatus 101 corresponding to the 2-tandem color printer, there arises a similar problem although it is not so serious as in the image processing apparatus 81 corresponding to the 4-tandem color printer.
Next, when the development is performed with particular emphasis on the image processing apparatus 81 corresponding to the 4-tandem color printer, there can be conceived a case where the development is performed with the Y-rendering processor 82, the M-rendering processor 85, the C-rendering processor 88, the K-rendering processor 91, the Y-output control unit 84, the M-output control unit 87, the C-output control unit 90, and the K-output control unit 93 as one 4-tandem ASIC. This 4-tandem ASIC may operate with a quarter of the performance of the 4-cycle ASIC, and can be implemented by the use of a package a little larger than the 4-cycle ASIC. For this reason, when the cost of the 4-cycle ASIC is assumed to be 1, the 4-tandem ASIC can be implemented at a cost of approximately 1.5 times as high as it. In the case of designing the image processing apparatus 81 corresponding to the 4-tandem color printer, the cost of the ASIC when one piece of the 4-tandem ASIC is used becomes approximately one third the cost when four pieces of 4-cycle ASIC are used, and it can be packaged on a small substrate, and therefore, it becomes possible to implement it on a low-priced substrate.
However, when the 4-tandem ASIC is used on designing the image processing apparatus 71 corresponding to the 4-cycle color printer, it is possible to design with one piece of 4-tandem ASIC, but it can be connected only to a 4-cycle color printer 1 having the one-quarter performance. Similarly, when the 4-tandem ASIC is used on designing the image processing apparatus 101 corresponding to the 2-tandem color printer, it is possible to design with two pieces of 4-tandem ASIC, but it can only be connected to a 2-tandem color printer 41 having the half performance.
When the performance and the system cost are optimized, it is necessary to individually develop the ASIC in accordance with each of the image processing apparatus 71 corresponding to the 4-cycle color printer, the image processing apparatus 81 corresponding to the 4-tandem color printer and the image processing apparatus 101 corresponding to the 2-tandem color printer, and the development expense and design man-hour increase three times. Also, the configuration of the color printer can be conceived in addition to the 4-cycle color printer 1, the 4-tandem color printer 21 and the 2-tandem color printer 41, and the performance is also advancing day by day. Therefore, there was the problem that the development expense and design man-hour would be enormous if individually developed.
In the above description, there has been shown a case of image processing for converting PDL into bit map data, and there has arisen the similar problem not only in such image processing, but also in various image processing such as a case of outputting to a printer while decoding, for example, bit map data encoded.
In the image processing apparatus 81 corresponding to the 4-tandem color printer and the image processing apparatus 101 corresponding to the 2-tandem color printer, plural rendering processors are provided to perform the processing in parallel. However, all the rendering processors in these image processing apparatuses process images having different colors in the same band. On the other hand, among conventional image processing apparatuses, some apparatuses, which process different bands in plural rendering processors, have also been developed. In an image processing apparatus described in, for example, Japanese Published Unexamined Patent Application No. Hei 6-214555, plural rendering modules are provided to process respectively-different rendering commands. Also, printing equipment described in Japanese Published Unexamined Patent Application No. Hei 10-151815 has plural expansion processors to expand into bit map data in respectively-different bands. In the technique described in these literatures, however, speedup due to parallel processing can be attempted, but no consideration has been given to the mechanism of an output device such as a printer. Therefore, in the case of outputting to such an output device having various mechanisms as described above, an output control unit suitable for the mechanism of the respective output devices must be separately designed. Also, the throughput capacity suitable for each mechanism as described above will be required, but such control as to perform processing corresponding to such throughput capacity has not been taken into consideration.
The present invention has been made in view of the above circumstances and provides an image processing apparatus made available irrespective of the mechanism of an output device to be connected thereto.
According to the present invention, there is provided an image processing apparatus for processing image data inputted to output to an output device, characterized by having plural image processing parts for processing image data inputted; a configuration control part for controlling configuration of plural image processing parts in accordance with a mechanism of the output device; a processing order control part for controlling image data to be inputted into plural image processing parts in accordance with the configuration of the image processing parts controlled by the configuration control part; and an output control part for controlling the output to the output device from the image processing parts in accordance with the configuration of the plural image processing parts controlled by the configuration control part.
If the output device is, for example, the above 4-cycle color printer, four image processing parts are used, the configuration control part controls so that the four image processing parts are configured so as to perform sequential processing in parallel, the processing order control part inputs image data to be sequentially outputted to the output device respectively into the four image processing parts, and the output control parts transmit output data to be outputted from the respective image processing parts to the output part in order. Thus, the four image processing parts are capable of processing, for example, Y-color, M-color, C-color and K-color in parallel respectively, and outputting in order. At this time, since respective image processing parts process in parallel, one quarter of the conventional throughput capacity will suffice.
In a case where the above 4-tandem color printer is used as an output device by the use of the same image processing apparatus, the four image processing parts are likewise used, the configuration control part controls so that the four image processing parts are configured so as to perform the processing in parallel, the processing order control part inputs image data to be outputted to the output device in parallel respectively into the four image processing parts, and the output control parts transmit output data to be outputted from the respective image processing parts to the output parts in parallel respectively. Thus, the four image processing parts are capable of processing, for example, Y-color, M-color, C-color and K-color in parallel respectively, and outputting in parallel.
Even when the output device is a 2-tandem color printer, it is, of course, possible to cope with. The configuration control part can control the four image processing parts so that they are constructed of two groups, which perform parallel processing, the processing order control part can input image data to be outputted in parallel to the output device into each of groups of image processing parts, and the output control part can control so that the output data from the group of image processing parts are transmitted in parallel to the output parts, and that the output data to be outputted from two image processing parts within the group are transmitted to the output part in order.
As described above, an image processing apparatus according to the present invention enables output devices having different mechanisms, various output devices such as a 4-cycle color printer, a 4-tandem color printer and a 2-tandem color printer, which are different in, for example, configuration at performance of NPPM, to be connected thereto, and it becomes possible to improve the performance by the use of plural image processing apparatuses even if the performance of the color printer exceeds NPPM.